Deep red is obtained by reducing the brightness on the basis of the original red, which is the brightness change in the red system. Low brightness.
The optical complementary color of red is cyan. Red is one of the three primary colors of light. It can be mixed with turquoise and indigo to produce any color.
Red is the color at the low frequency end of the visible spectrum, which can stimulate the observer's vision through energy. The frequency is 380 ~ 480 Hz (corresponding to the wavelength in the air is about 780 ~ 620 nm), which is similar to the color of fresh blood.